1. Field of the Invention
The present invention relates to optical laser technology, and particularly to a multi-wavelength laser configured to provide stable multi-lasing over a variety of temperatures and time durations.
2. Description of the Related Art
Fiber ring lasers have been extensively investigated in the recent past. Hitherto, many applications of multi-wavelength fiber lasers have been found in optical fiber sensors, optical communications and optical instrument testing. These light sources are attractive, as their compact size and increased number of wavelengths per component make them very cost-effective. Various methods have been put forward for the generation of such sources. Typically, Erbium-Doped-Fiber (EDF) lasers using a comb filter are seen to be a potential candidate in generating multi-wavelength laser sources, since the EDF provides large gain, high saturation power and a relatively low noise figure. However, due to the homogenous broadening mechanism of the EDF laser at room temperature, the number of lasing modes is limited to generally less than four. In addition, the mode competition leads to fluctuating and unstable laser powers.
Overcoming these issues requires either cooling the EDF with liquid nitrogen or using costly twin-core EDFs, both of which are complex and costly methods, which are not practically viable. One proposal is using a multi-wavelength erbium-doped fiber laser based on inhomogeneous loss mechanism by use of a highly nonlinear fiber and a Fabry-Perot filter. In order to overcome the effect of inhomogeneous line broadening of EDF, a hybrid gain medium has been proposed. The hybrid gain medium consisted of a diode pumped EDF along with a semiconductor optical amplifier in the same cavity. The reported results showed an improvement in terms of mode hopping, compared with the previously reported findings.
Other methods have also been developed to generate multi-wavelength sources, most notably using either Brillouin scattering, or by slicing the amplified spontaneous emission (ASE) from a linear gain medium. Recently, semiconductor optical amplifiers (SOAs) have been the focus of interest for signal amplification in optical networks. SOAs offer many salient features. These devices are compact, lightweight, consume low power, and are easily mass produced and integrated with other optical components on a chip, making it an attractive alternative to fiber-based products. The most important property of the SOA is its dominant inhomogeneous broadening. This property helps in realizing multi-wavelength laser sources employing semiconductor-based gain media suffering from minimum mode competition. It has been proposed to use a conventional SOA as a gain medium for multi-wavelength generation. The result is generating over 40 channels with a channel spacing of 0.5 nm. Yet improvements are still sought.
Thus, a multi-wavelength laser solving the aforementioned problems is desired.